Another Channel Master SMC 1m20 restoration X2

[Channel Hopper]

Reflective paint will degrade the LNB unless the dish is in a high latitude.

There are some protective systems (moving dish when there is a chance of sun-out) or replacing the front end components regularly.

 

[teltras]

Yes, thats what people say...

But the antenna it´s not a mirror, It´s very hard for me to believe that. What happens when direct sunlight enters from the front cover of the lnb?

I never seen a melted one and we have lots of sunlight and very high temps during the summer, May to October.

 

[zorrin]

Why reflecive was a mistake?

I did paint my CM/Andrew antennas with 2 compound Hempel Polyurethane paint RAL 7035 and RAL 7038 and I found 7038 is the original CM colour.

I think this paint it will last forever. It looks like a layer of plastic protecting the antenna. This summer I had in my region 46ºcelcius, the paint looks like it was painted today. I painted my antennas in May 2021,

The problem of a reflective paint has nothing to do with the antenna but with the reflection of the sun on the LNB which is at the focal point of the dish.
The antenna becomes a solar oven and the LNB a pressure cooker...
You therefore need a matte paint which does not reflect the rays.
It is possible that a dark color heats up the reflector and deforms it slightly.
It's always less serious than cooking the LNB...
In my opinion a matte light gray is the basic solution.
but in green they are too stylish, aren't they?

 

[Channel Hopper]

Yes, thats what people say...

But the antenna it´s not a mirror, It´s very hard for me to believe that. What happens when direct sunlight enters from the front cover of the lnb?

I never seen a melted one and we have lots of sunlight and very high temps during the summer, May to October.

You probably have a bent dish.

 

[teltras]

The problem of a reflective paint has nothing to do with the antenna but with the reflection of the sun on the LNB which is at the focal point of the dish.
The antenna becomes a solar oven and the LNB a pressure cooker...
You therefore need a matte paint which does not reflect the rays.
It is possible that a dark color heats up the reflector and deforms it slightly.
It's always less serious than cooking the LNB...
In my opinion a matte light gray is the basic solution.
but in green they are too stylish, aren't they?

Green is fine, because you have vegetation.

I don´t agree with you about the reflective paint, it simply does not make any sense about the pressure cooker, CM does not have a smooth surface as you know.
I understand what you are trying to say but it simply does not pop the cap off or damage the internals of the lnb. It´s all metal inside the waveguide.
I would worry more about black lnb in our sun over here, I think they could hit 65/70º celcius. LNB must be cooler, the more cooler the better.
My antenna is light grey and its working fine

You probably have a bent dish.

Actually no, at the sun with light grey colour the antenna maybe reach 50/55 celcius no more than that.

CM does not bend or warp, fortunately.

 

[Manikm909]

lovely green dish @zorrin

 

[ozumo]

LNB must be cooler, the more cooler the better.

Exactly.

 

[teltras]

Exactly.

OMG, Thats a mirror, its silver, not white or grey! Sure a mirror can do that.

No way to achieve it that with any other colours except silver or gold on a smooth surface. CM/andrew does not have a smooth surface. And its not golden or silver.

 

[ozumo]

OMG, Thats a mirror, its silver, not white or grey! Sure a mirror can do that.

No way to achieve it that with other colours except silver or gold on a smooth surface. CM/andrew does not have a smooth surface.

A painted dish will still focus sunlight onto the LNB, more-so when it is glossy/shiny. Like you said, the cooler the better.

 

[teltras]

A painted dish will still focus sunlight onto the LNB, more-so when it is shiny. Like you said, the cooler the better.

Agreed, But its impossible to achieve that even with shiny white.

My dish focus the sun every single day.

Where do you guys live? Saudi Arabia? Even there its impossible, I worked there its hell on earth.

 

[ozumo]

Agreed, But its impossible to achieve that even with shiny white.

My dish focus the sun every single day.

Twice a year a the sun will be directly behind the satellite AKA solar outage. That is when the dish will focus light directly onto the LNB. Of course it will have a lesser effect if the dish is not a mirror finish but it will still heat up the LNB. It doesn't have to melt it to have negative effect.

 

[teltras]

Correct. And the sky could have clouds in those days...at that precise time.

Thanks

 

[Channel Hopper]

The sun doesn't put out just visible light.

Sunlight - Wikipedia

en.wikipedia.org

 

[zorrin]

At night every thing is fine

 

[Channel Hopper]

Twice a year a the sun will be directly behind the satellite AKA solar outage. That is when the dish will focus light directly onto the LNB. Of course it will have a lesser effect if the dish is not a mirror finish but it will still heat up the LNB. It doesn't have to melt it to have negative effect.

Only if the dish is pointing at the satellite at the time of outage. Steerable systems will be able to move off the point of outage before it occurs.

 

[zorrin]

the feed arm supports are in place.
I'm looking for the best place to create the fine height adjustment of the arm and make it more solid when the antenna is full east or west.
The idea is to have a support for each LNB and avoid adjustments at each change, a sort of quick assembly system.



and most importantly, I have fans of my antennas !

 

[RimaNTSS]

I think that with such a long and massive bottom-feedarm you will always have play at the end of it, especially when the antenna is at the end positions. I hope I am wrong. Good luck with that.
And nice pets you have there!

 

[zorrin]

I think that with such a long and massive bottom-feedarm you will always have play at the end of it, especially when the antenna is at the end positions. I hope I am wrong. Good luck with that.
And nice pets you have there!

Yes, that's precisely the risk I'm trying to limit...
The upper arms will be attached as now to the new one.
and I will also reinforce the rear...
But my idea is to make my own polar mount in the end.

Yes I have very cute dogs

 

[zorrin]

For my first welding test I tested a new layout of the elevation motor.
It's better with the threaded rod but this part is too short and the azimuth motor touches the other...
Reinforcements will also be needed.

 

[zorrin]

A little update on my project.
I finished the adjustable fixing system of the central arm.
The motor of the multi LNB is in place too.
It remains to find how to fix the side arms and choose the final length of the central arm.
I also need to make the rear binding more rigid.